Normally off GaN/AlGaN HEMTs (high electron mobility transistors) are difficult to manufacture with sufficiently high threshold voltage and low RDSON*Area FOM (where RDSON is the on-state resistance of the transistor and FOM is the transistor's figure of merit). In most applications, the normally-off device concept is highly preferred over the normally-on device concept, e.g. with respect to safety operations at fail, or to be compatible with standard drivers, etc. With the introduction of a non-planar normally off GaN HEMT concept, a high performance device with respect to high threshold voltage and low RDSON*Area can be realized by creating a step in the gate region. However, in conventional non-planar normally off GaN HEMTs, the strongest (peak) channel arises at the AlGaN/gate insulator interface along the step in the gate region, where electrons cannot be supported from the main 2DEG (two-dimensional electron gas) channel because the barrier between the GaN/AlGaN interface must be overcome. This internal resistance leads to an improper transfer characteristic with poor threshold voltage control and high drain current (e.g. 1E-5 or higher) at even zero gate voltage, yielding a poorly functioning transistor. As such, a non-planar normally off GaN HEMT having a proper transistor transfer characteristic is desired.